ML20203P588

316(b) Cooling Water Intake Assessment,1985 Annual Rept

ML20203P588
Person / Time
Site:	Diablo Canyon
Issue date:	12/31/1985
From:	TERA CORP.
To:
Shared Package
ML20203P584	List: ML20203P583 ML20203P588 ML20203P597
References
NUDOCS 8605070498
Download: ML20203P588 (18)

Text

1 ATTACHMENT 2 _

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DIABIA CANTON POWER PLAET 316(b) COOLIEC WATER INTAKE ASSESSMENT 1985 AMNUAL REPORT i

Prepared For:

Pacific Gas and Electric Company 77 Beale Street

! San Francisco, California Prepared By:

Tera Corporation 2150 Shattuck Avenue Berkeley, California C:

April 1986 F

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DIANA Castos 316(b) 1985 AMDAL REPOET INTRODUCTION L

{ g Pacific Gas and Electric (PGandE) has initiated a biological i monitoring program at the Diablo Canyon Power Plant in accordance with

' I Section 316(b) of the Clean Water Act (Act) and Provision D4b of" NPDES

! Order 85-101. Section 316(b) of the Act requires that .... the location, design, construction, and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environmental impact." Because no single intake technology 1 can be considered to be the best technology available for all sites, a

}i " site-specific analysis of intake-related organism losses was initiated j at the Diablo Canyon Power Plant. Intake-related losses considered in j this program are those result-ing from entrninnent (the drawing of

, organisms into the cooling water system) and impingement (the j retention of organisms on the intake screens). Two complementary monitoring programs have been designed to quantify the entrainment and

! ,;. impingement of fish and macroinvertebrates at the plant. The programs -

j L vere specifically designed to provide the information necessary to support an analysis of feasibility, engineering constraints, and

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7, biological effectiveness of the existing and alternative' intake i ~

technologies which will provide a sufficient basis for regulatory agencies to determine whether the existing cooling water intake 3 , structure reflects the best technology available.

] v The objectives and methods of the major elements of the 316(b) program l were described in an updated study plan submitted to the Regions 1 i j Water Quality Control Board - Central Coast Region in 1983 in r; accordance with provisions of the Diablo Canyon Power Plant NPDES j permit. The monitoring -program was initiated in January 1985 with the

commencement of Unit 1 operation. Major elements of the program initiated during 1985 dealt with the compilation and documentation of inf ormation on (1) the opa' rational characteristics of the cooling.

water systems and source waterbody; (2) entrainment 'and impingement of organisms; (3) waterbody monitoring to establish a basis for evaluating potential population changes resulting from entrainment and impingement losses; ar.d (4) the assessment of alternative intake p technologies. This report provides ~a brief. overview of the status of 3 these major elements of the 316(b) monitoring program.

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]'a 316(b) NOEITnamc PROGRAM STATUS 9 The 1985 monitoring program schedule and corresponding status of Units 1 and 2 cooling water system operations are shown in Figure 1. A total j] [,l of 476 hours0.00551 days <br />0.132 hours <br />7.87037e-4 weeks <br />1.81118e-4 months <br /> of entrainment monitoring and 1,234 hours0.00271 days <br />0.065 hours <br />3.869048e-4 weeks <br />8.9037e-5 months <br /> of impingement.

8 monitoring was completed during 1985. In addition, 554 entrainment

] ,; support samples, collected from various intake and discharge asapling j j locations, were analyzed to provide a basis for selecting a l"1

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representative sampling location for the entrainment monitoring program. Impingement support studies completed during 1985 included 13 direct release experiments representing a total of 860 ' organisms. The

1) _ 1985 impingement program was augmented by 13 underwater fish jj

• observation surveys. A brief discussion and overview of the objectives, methods, and results of the major. study elements '

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i associated with the monitoring program is presented below.

[ Plant Operatiosa and Physical Data f The objective of this element of the program is to compile information j on the design and actual operation of the Units 1 and 2 cooling water

g !I, systems with emphasis on those design and operational parameters i- necessary for the interpretation of information collected in the 1

entrainment and impingement studies. Data on intake screen rotation L frequency, detrital loading, circulating water pump operation, biofouling control procedures, intake and discharge water ll:

y l temperatures, and general water quality parameters such as salinity and dissolved oxygen concentrations was compiled during 1985.

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i Unit 1 and 2 cooling water volumes and net generation levels during l 1985 are shown in Figurs 2. Cooling water volumes varied substantially j+ L[ throughout the year depending on operation and testing of the two ,

units. Cooling water volumes between January and July primarily 4;, ,

reflect operation of the Unit 1 cooling water system (maximum flow, .

1.21 billion gallons per day). The increase in cooling water volumes to a level of approximately 2.4 billion gallons per day which occurred

between July and December reflects the combined flow associated'with

testing and operation of both Units 1 and 2.

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Estratament Studies The entrainment studies include two complementary study elements:

entrainment abundance and entrainment survival. The entrainment  ;

y' l abundance studies emphasized on planktonic early life stages of fish (ichthyoplankton) and selected target sacroinvertebrate taxa.

Macroinvertebrates selected as target organisms include amphipods, I

,, sysids, decapod crustaceans, and molluscs-(the planktonic larval y!

& stages of class and abalone). 'These ascroinvertebrate taxa were selected based on their sport and commercial importance and/or their r role as important prey for juvenile and adult fish inhabiting the '

area. The entrainment survival studies -focussed on ichthyoplankton R ['

and selected crustaceans.

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• FIGURE I DIABLO CANYON POWER PLANT l 1985

SUMMARY

OF FELD COLLECTION ACTIVITES

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COOLING WATER VOLUME - UNITS I AND 2 COMBINED

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FIGURE 2 AVERAGE WEEKLY DIABLO CANYON UNITS I AND 2 COOLING WATER VOLUMES AND POWER LEVEL,1985 I

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4 Entrainment Abundance The entrainment abundance study has been designed to provide quantitative information on (1) the species composition of entrained ichthyoplankton and selected sacroinvertebrates; (2) the size (length) composition of the entrained ichthyoplankton; and (3) the seasonal and diel distribution patterns for entrained biota. In addition, a number of specific entrainment collections (entrainment support studies) were made during 1985 to provide the necessary information upon which the sampling design and selection of representative sampling locations for the routine monitoring program could be based. Entrainment support studies conducted during 1985 tested the hypothesis that organism densities in the cooling water discharge are representative of the

{ overall density of organissa entrained into the cooling water intake.

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Prior to initiating the routine entrainment monitoring program, tests were conducted at the site to document the efficiency of the I

entrainment sample collection and processing techniques. Based on results of these tests and previous studies conducted at other power plant sites, it was concluded that a pump sampling system and 335-um mesh plankton net would be effective for use in the routine monitoring program.

As part of the entrainment support studies, collections were made from various intake and discharge sampling locations during February and June 1985. Larval fish (ichthyoplankton) were selected as the target taxa for use in the analyses. Af ter considering the variation in larval fish densities observed in collections from the intake attributable to vertical stratification in the water column and the lack of significant differences betwetn the intake and discharge -

i densities, it was concluded that a discharge sampling location would be representative of densities of larval fish entrained into the

r. cooling water system. Based on results of these tests, it was concluded that the center mid-depth discharge sampling location provided a representative sample of entrained organisms and was therefore selected for use in the routine entrainment monitoring program. Additional entrainment support studies are scheduled for 1986 to provide further confirmation on the selection of representative sampling locations for use in the routine entrainment nonitoring program.

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The routine entrainment monitoring program was initiated in October 1985 with samples collected from a sampling pipe located at mid-depth in the center of the Unit I discharge. Entrainment samples were

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collected with a 10.2-ce diameter pump and 335-um mesh plankton not l

during 24-hour sampling periode scheduled twice per week during the winter season of anticipated peak larval fish abundance. Each discrete

- entrainment sample represents a collection duration of approximately 60 minutes and a sample volume of approximately 55 cubic meters.

Following collection, entrainment samples were preserved and subsequently processed to identify and enumerate larval fish and selected macroinvertebrate taxa. All sample collection and processing

, was performed in accordance with standard procedures and was subject

to quality control an1 quality assurance audits and validation.

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1 During 1985 a total of 476 one-hour entrainment abundance samples were i collected from the Unit 1 cooling water discharge. Sample sorting for j "

larval fish has been completed for 287 entrainment abundance. samples (60 percent) collected in 1985. A total of 119 of the samples which j had been initially sorted (41 percent) have been resorted as part of j the ongoing quality control program.

'l Larval fish representing nine families were identified in preliminary

} - taxonomic identifications made from a series of 54 selected j entrainment samples collected between October and December 1985.(Table

. 1). The most abundant species identified in the selected entrainment 4 samples were larval cabezon, northern anchovy, sculpins, and white

/, croaker which collectively represented 78 percent of the larval fish j present in these selected samples. The length distribution of M entrained larval fish (all taxa combined) indicates that the majority L-of ichthyoplantkton entrained during October-December 1985 period were l}. less than 10 mm long: >

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Length Class Percent Prequency .

! (mm) October November December Total l '< 5.0 78 73 49 65 5.1 - 9.9 19 21 26 22- 1

( >, 10.0 3 6 25 13 ii j' Northern anchovy represented 92' percent of the larval fish collected ql which were equal to or greater than 10 aus long.

,, Routine entrainment abundance sampling is scheduled to continue .

. [~ through October 1986. Entrainment sampling is scheduled for two 24-

hour periods per week through March 1986 and one 24-hour period per ji week between April and October 1986. In addition, offshore plankton

[ collections are scheduled to occur once per week between March and 1 October 1986 in conjunction with routine entrainment abundance

I sampling. This sampling will be conducted at two sampling stations l along the coast using a towed plankton net to provide additional information on the relationship between species composition and relative densities of planktonic organisms observed in the cooling water samples and those in the near-shore source waterbody.

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.. Entrainment Survival

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The entrainment survival program has been designed to determine the

,' proportion of larval fish and ascroinvertebrates not surviving

! entrainment. Protocol for this study includes the' simultaneous l

jl collection of organisms from the intake and discharge of the cooling water system. The sample collection equipment used in the entrainment l survival studies has been designed specifically for the collection of

!! ' larval fish and macroinvertebrates erf th a minimum of sampling induced

j stress. Once collected, the organisms are held in the onsite

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y T4le 1. Species

ornposition for ichthyoplankton collected in selected entrain-ment samples at Diablo Canyon Unit I, October-December,1985.(o) -

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Scientific Name Common Name Composition i

i Scorpoenichthys mormoratus Cabezon 31 i

i7 Enoroulis mordax Northern anchovy 19 Cottidae Sculpin iS Genyonemus lineatus White crooker 13 Gibbonsio sp. Kelpfish 8 Coryphooteris nichoisi Blockeye goby 3 Hypsopsetto guttalato Diamond turbot I i

Gobblidae Gobies 2 I Oligocottus sp. Sculpin 2 i

Heterostichus rostratus Giant kelpfish  !

,L Artedius sp. Sculpin 1 Clinidae Clinids l 1'

Atherinopsis californiensis Jacksmelt <l j Neoclinus sp. Fringehead <l Lepidonobius lepidus . Boy goby <l I

Goblesox moeondricus Northern clingfIsh <l i Leptocottus armatus Pacific stoghorn sculpin <l ,

Osmeridae Smelt <l Unidentified larvae I i l

.lg Note: (a) Entrainment samples collected between 1800 and 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br /> on nine

j. sampling days between October 17, and December 10,1985.

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1aboratory to determine initial and delayed nortality for a 96-hour observation period. The proportion of entrained individuals of each selected taxon not surviving entrainment can then be estimated by determining the proportion dead in the cooling water samples collected f rom the discharge relative to the proportion dead in the control samples collected f rom the intake. The intake samples are used to account for mortality resulting from sampling and other natural causes not related to entrainment.

Entrainment survival sampling was initiated during December 1985 at sampling locations located in the center of Unit 1 intake forebay 1-2 at mid-depth and in the center of the Unit 1 discharge above the top.

weir at mid-depth. Although the number of organisms ohserved was insufficient to quantify entrainment survival, it was evident during December that larval fish and invertebrates were alive in samples collected from the Unit 1 discharge.

The low densities of larval fish observed in survival collections completed to date, however, pose a significant obstacle in the collection of a sufficient number of larval fish from both the intake l

and discharge to effectively quantify entrainment survival. Results of 1 previous larval fish surveys in the vicinity of the Diablo Canyon Power Plant support the lou densities of larval fish observed in entrainment survival samples. - Analysis and interpretation of the i

entrainment survival data may be complicated by the problem of low.

I numbers of larval fish in the survival collections and high' variability in entrainment survival over a range of life stages and lengths and between species (e.g., cottids typically exhibit c relatively high entrainment survival while larval anchovy characteristically have low survival). Following completion of the January-March sampling, preliminary results of the entrainment survival collections will be reviewed and modifications and alternatives to the study design will be evaluated.

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I Impingement Studies ,

l The impinge". ant studies include two complementary study elements:

impingement abundance and impingement surviva!. All organisms'

< collected during the impingement studies are documented with primary emphasis on juvenile and adult stages of fish and selected target

{. macroinvertebrate taxa. Macroinvertebrates selected as target organisms include arthropods (particularly decapod crustaceans),

molluscs, gastropods, and echinoderms. These sacroinvertebrate taxa ,' n

- were selected based on their sport and commercial importance and/or _

their role as important prey for juvenile and adult fish. inhabiting , _

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o Impinsement Abundance 7

{ The impingement abundance study was designed to prov.ide the  :

quantitative information necessary to:

(1) Determine the species composition of the organisms impinged '

j (2) De termine the lengths and weights of selected impinged j organisms

! (3) Determine the diel and seasonal patterns of impingement (4) Examine the relationship between impingement and cooling I water system operational parameters (5) Determine the sex ratio and degree of gonadal maturity for selected species (6) Determine whether or not any significant impingement occurs on the intake bar racks.

A series of tests was conducted at the site during 1985 to document j the ef ficiency of the impingement sample collection and processing i techniques. Periodically, a known number of marked dead fish were

released directly into the screenwash sluiceway prior to screen

! rotation and washing. The proportion of marked organisms subsequently i 4 i recovered in the collection baskets during sample processing provided information on sample collection and processing efficiency. Three direct release tests were conducted during 1985 at the Units 1 and 2

,  ! screenwash sluiceways in which 100 percent of the fish released were recovered in the impingement collection basket. Based on results of

j these tests it was concluded th'at the impingement co11setion basket i would be effective for use in the routine impingement monitoring program.

i A second series of tests was conducted.in which a known number of marked dead fish and macroinvertebrates were released between the bar racks and the traveling screens. The number of marked organisms subsequently collected in the impingement samples provided inforestion

{~ on the collection ef ficiency of the system. Results of the initial series of direct release studies, conducted between May and July, indicated that recovery of released dead organisms was substantially lower than expected (less than 50 percent recovery) based on results

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of similar direct release tests conducted at other power plant intakes. Because of the relatively low recovery of released organisms

. I~ at the Diablo Canyon intake, a more intensive series of direct release L tests was initiated along with surface and underwater observations of 3 the organisms duriny impingement and subsequent screen rotation and '

i cleaning. The direct observations suggested that in part the low

recovery of impinged organisms was the result of debris (kelp) accumulating in the intake forebay which was not effectively removed

. by rotation of the intake screens. When the screens were rotated for washing, lapinged material (including help and organisms) fell off of i

the screen aesh af ter the material passed through the air-water

) interface, accumulating in the intake forebay rather than being washed j

from the screen into the collection basket.- The intake screens were

4 subsequently modified to improve the removal of impinged kelp. Results of direct release tests conducted between September and December indicate that recovery efficiency has increased 'substantially. .l i

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Recovery efficiency in the more recent tests has increased to levels between 60 and 95 percent. Results of the recent direct release tests are consistent with results of similar tests conducted at other power

- plants.

The routine impingement monitoring program was initiated in February 1985 with samples collected from the Unit 1 intake screens.

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Impingement collections were subsequently made from both the Unit 1 and Unit 2 intake screens when circulating water pumps were in operation at the units (Figure 1). Impingement samples were collected 3 during 24-hour sampling periods scheduled once per week during 1985.

Intake water temperature, dissolved oxygen, tidal height, and circulating water pump operations were recorded for each impingement sample collected.

Immediately prior to each sampling period, intake screens were rotated and washed to remove previously impinged organisms and debris. The '

7; intake screens then remain stationary for approximately 3-3/4 hours and were then rotated for 15 minutes while impinged organisms and debris were washed into a collection basket. This cycle of stationary period and rotation was then repeated throughout the 24-hour sampling period (except on those occasions when high detrital loads required continuous screenwashing for the 24-hour sampling period). After each collection, fish and macroinvertebrates were sorted by hand from the l'_ detritus. Fish and selected macroinvertebrates were identified to species, counted, measured, and weighed. The remaining ascroinvertebrates were identified and counted. All sample collection i and processing was performed in accordance with standard procedures ,

L and was subject to quality control and quality assurance audits and ,

validation.

During 1985 a total of 38 impingemant collections were made at Unit 1  !

representing a total of 897 hours0.0104 days <br />0.249 hours <br />0.00148 weeks <br />3.413085e-4 months <br /> of sampling. A total of 15 ,

impingement collections were made at Unit 2 representing a total of 337 hours0.0039 days <br />0.0936 hours <br />5.57209e-4 weeks <br />1.282285e-4 months <br /> of sampling. The numbers of the most abundant fish and

'3 macroinvertebrates collected during the 1985 impingement collections are presented in Table 2. During 1985, a total of 240 fish were 7 collected in the impingement studies at Unit 1 and 97 fish were .

,. collected at Unit 2. The four most abundant fish species collected at  :

l Unit 1 included the yellowtail rockfish (32 collected), shiner

- surfperch (17 collected), thornback ray (18 collected), and the olive rockfish (12 collected). The three most abundant sacroinvertebrates a collected at Unit I were the rock crab (774 collected; primarily a juveniles), sharpnose crab (520 collected), and the purple sea urchin  !

{ (423 collected). l

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The temporal distribution in impingement of selected fish and y ascroinvertebrates at the Unit 1 intake is shown Figures 3 and 4 along with the corresponding cooling water volumes for each sampling date.

{ Impingement has been standardized as a catch per unit effort

, (number /24 hours). Fish were present in impingement samples i y < throughout the year. The highest impingement occurred in late July at- I j 'd a level of approximately 22 fish per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (Figure 3). The  !

• majority of surfperch and rockfish were collected during the susmer. .

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T41e 2. Numbers of selected fish and macroinvertebrates collected in Diablo Canyon impingement samples, February-December,1985.

Number Taxon Collected Scientific Name Common Name Unit i Unit 2 m Fish r, Sebastes flavidus Yellowtail rockfish 32 15 Cymotogaster aggregata Shiner surfperch 17 0

, Sebastes serranoides Olive rockfish 12 2 Platyrhinoidis triserioto Thornbock ray 18 26 Porichthys nototus Pjoinfin midshipman 10 6 Torpedo californico Pacific electric ray 9 0 Other fish 142 48 Total fish 240 97 Macroinvertebrates J

Concer antennarius Rock crab 774 218 Scyra ocutifrons Sharpnose crab 520 353

{~ Strongylocentrotus purpurotus Purple sea urchin 423 191 Pugettio richil Spiny kelp crab 280 325 Colliostoma ligatum Bluetop snoll 301 177 Tegulobrunnea Brown turban snoll 268 188

- Pugettio producto Northern kelp crab 246 102 Hinnites giganteus Rock scallop 229 28 h Octopus spp. Octopus i16 69 h Note: Unit I collections represent 897 hours0.0104 days <br />0.249 hours <br />0.00148 weeks <br />3.413085e-4 months <br /> of sampling.

Unit 2 collections represent 337 hours0.0039 days <br />0.0936 hours <br />5.57209e-4 weeks <br />1.282285e-4 months <br /> of sampling.

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UNIT l COOLING WATER VOLUME i

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FIGURE 3 l COOLING WATER VOLUMES AND NUWERS OF FISH l l lMPINGED AT TE DIABLO CANYON UNIT I INTAKE, FEBRUARY-DECEWER,1985 12 l

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TIME (months) i FIGURE 4 l COOLING WATER VOLUMES AND NUM3ERS OF l i

' SELECTED MACROINVERTEBRATES IMPlNCED AT THE l DIABLO CANYON UNIT l lNTAKE, FEBRUARY-DECEMBER,1985 l

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i The temporal distribution of selected sacroinvertebrates_ collected in i Unit 1 impingement samples (Figure 4) was considerably more variable

! - than the seasonal distribution patterns observed for fish. The 2 gessonal distribution for impinged rock crabe (Cancer antennarius) is

shown in Figure f. for both juvenile and adult rock crabs. Rock crabs, l _

the most abundant sacroinvertebrate collected, were present throughout the year although the period of highest impingement occurred during the fall (impingement of approximately 90 per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> occurred in

late October). Of rock crabs (Cancer antennarius) collected, 96 percent were juveniles (Figure 5).

The routine . impingement. collections were augmented by periodic underwater inspections made using scuba. The diver observations provide additional information on the relative abundance and species

, composition of fish inhabiting the area immediately adjacent to the  :

2 bar racks and intake forebays. The diver observations also provided information on impingement on the bar racks.

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The diver observations made in the immediate area of the intake bar i racks indicate that a relatively diverse community of fish (particulary juveniles) and invertebrates is present. The cooling

water intake structure provides habitat for surfperch, rockfish, kelpfish and a number of other fish. Fish have been frequently I_

observed residing and foraging within the intake forebays and along the bar racks. The fish have been observed to move readily between forebays and to move into and out of the intake structure independently of cooling water system operations. Impingement on the ,

l bar racks has been limited to a low number of thornback and electric rays.

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Impingement Survival ba The basic objective of the impingement survival program was to determine the proportion of fish and macroinvertebrates not surviving

4. impingement. Because of the low numbers of impinged organisms, particularly fish (Table 2), initial impingement survival observations recorded at the Diablo Canyon Power Plant will be augmented by results of impingement survival studies conducted at the Moss Landing Power

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Plant and at other cooling water intakes. Preliminary analysis of

}_U initial impingement survival results from the Diablo Canyon Power 9 Plant and initial and long-term impingement survival at other sites

)[ indicate that survival of species such as northern anchovy is low

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iL while species such as plainfin midshipman and sculpin are able to

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l survive impingement on intake screens. Additional impingement survival.

data is being compiled for marine fish and invertebrates ' impinged under various intake screen operating conditions (e.g., rotation j frequencies) from studies conducted at other sites to complement the

initial survival observations made at the Diablo Canyon Power Plant.

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6.._..-,.._ _ ._ . - . _ __ _,___ . .i_ m __...._,.m... _ _ . _ . , . . _ . , _ . _ . _ _ . . , _ , _ - . . . . , _ . _ _ _ . _ . . . . . . . _ _ . .

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t 100 90 ADULT 90 JUVENILE 70-en E 60 -

Z g 50 -

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20 -

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OCT NOV DEC TIME (months) i .

l FIGURE 5 NUMBERS OF JUVENILE AND ADULT ROCK CRABS (C. ANTENNARIUS) IMPINGED AT 4

THE DIABLO CANYON UNIT I INTAKE, FEBRUARY - DECEMBER,1985 i

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Waterbody Monitoring ,

4} Data exist from a number of monitoring programs, creel surveys, and

'{ research investigations conducted in the general vicinity of the j power plant site which can be used to establish a quantitative

!j baseline for evaluating the information collected in the entrainment W and impingement monitoring programs. Sport fishing statistics (catch

h and effort records) from the California Department of Fish and Game

$ catch blocks in the general vicinity of the plant site and commercial ij landing records are being compiled to eramtne general trends in the j catch statistics. Additional sport fishing data is available from a

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creel census which has been conducted by PGandE in the vicinity of the j Diablo Canyon Power Plant since 1979. Life history information (geographic distribution, habitat preference, relative abundance, i fecundity and repoductive potential, natural survival rates, harvest rates, etc.) for the key fish and ascroinvertebrate species selected for use in the entrainment and impingement monitoring programs is also i being compiled. The baseline information on historic trends in I

abundance and the life history information will provide a species-specific basis for assessing the potential affects on these populations resulting from cooling water system operation.  !

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, 4Information sources contacted during 1985 include, for example, the jj California Department of Fish and Game Marine Recources Region, the

!j National Marine Fisheries Service, Scripps Institute of Oceanography, j the Moss Landing Marine Laboratory, and many studies conducted at the '

i Diablo Canyon site. The compilation of information includes both published and unpublished material. Compilation of source waterbody i

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information was initiated in January 1985 and will continue thoughout i the duration of the program.

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Assessment of Alternatives

'i  ;

The assessment of alternative intake technologies which could potentially reduce entrainment and/or impingement impacts at the Diablo Canyon Power Plant was designed to follow a hierarchical evaluation system. The major steps undertaken in this evaluation j include:

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(1) Identification of alternatives i l (2) Preliminary assessment of each alternative ii ~

(3) Description and conceptual design of - the technically feasible alternatives (4) Environmental assessment of feasible alternatives i ;a (5) Comparative analysis of alternatives including

!j consideration of total cost and corresponding

, envirounental benefits.

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l The emphasis during 1985 focussed on a continuing compila, tion of i! _

information being gathered at other power plant sites and through j laboratory studies on the operational performance, reliability, and 1 effectiveness of various technologies for reducing the combined

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effects of entrainment and impingement on fish and invertebrates.

) Information sources include state and federal agencies (e.g.,

California Department of Water Resources and California Department of i Fish and Game), utility sponsored research organisations such as EPRI,

! other utilities and water diversion projects, studies and evaluations t 6 conducted by PGandE, and manufacturers. The compilation of generic i information on engineering and biological performance of alternative technologies will provide a basis for the site-specific assessment of

, alternatives for the Diablo Canyon Power Plant. The compilation of j infonation on alternative technologies will continue throughout the duration of the project.

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